Web deployment task build failed

I encountered the same issue when building via TFS. When I tried to manually import the website I got a more informative error: "not able to log on the user \WDeployConfigWriter".

Turns out that when you install web deploy it sets up two local accounts WDeployConfigWriter and WDeployAdmin. The passwords on these accounts are set to expire. So reset the passwords on the web server and set to "never expire". Then go to Management Service Delegation in IIS. Each of the presented rules has a UserName field. Where it is WDeployAdmin or WDeployConfigWriter right click and update the credentials to the new passwords.

A full explanation with screenshots can be found here: http://workinghardinit.wordpress.com/2011/07/18/wdeployconfigwriter-account-issues-trouble-shooting-web-deploy-2-0-with-lessons-learned/

All you have to do is re-run the script "AddDelegationRules.ps1" located in "C:\Program Files\IIS\Microsoft Web Deploy V3\Scripts\"

This is the script that is run when web deploy is first installed. It will re-create any missing delegations, re-set the passwords for both WebDeployAdmin and WebDeployConfigWriter, and add WebDeployAdmin back to the Administrators group.

You would still need to set the password on each account not to expire after re-running the script.

We had the same issue-- in our case we are only using MSDeploy (without TFS). Resetting the password for those 2 local accounts (WDeployConfigWriter and WDeployAdmin) solved the problem as their passwords had expired. We attempted to change the password policy to never expire, but only a local Administrator can do that.